Question

先化简 后求值(x-1分之3-x-1)/(x^2-2x+1分之x-2) 其中x=3倍根号2-2

Answer 1

=[3/(x-1) -(x+1)(x-1)/(x-1)]÷(x-2)/(x-1)²

=(3-x²+1)/(x-1)×(x-1)²/(x-2)

=(2-x)(2+x)(x-1)/(x-2)

=(2+x)(1-x)

=(2+3倍根号2-2)(1-3倍根号2+2）

=3√2 (3-3√2)

=9√2 -18